Power control in a medical ventilator

ABSTRACT

A ventilator that is small, lightweight, and portable, yet capable of being quickly adapted to operate in a plurality of different modes and configurations to deliver a variety of therapies to a patent. A porting system having a plurality of sensors structured to monitor a number of parameters with respect to the flow of gas, and a number of porting blocks is used to reconfigure the ventilator so that it operates as a single-limb or dual limb ventilator. In the single-limb configuration, an active or passive exhaust assembly can be provided proximate to the patient. The ventilator is capable of operate in a volume or pressure support mode, even in a single-limb configuration. In addition, a power control mechanism controls the supply of power to the ventilator from an AC power source, a lead acid battery, an internal rechargeable battery pack, and a detachable battery pack.

This patent application claims the priority benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 61/106,330 filed on Oct. 17,2008, the contents of which are herein incorporated by reference.

The invention relates generally to medical ventilators and, moreparticularly, to a medical ventilator that is relatively small,lightweight, and portable, yet is capable of being quickly and easilyadapted to operate in a plurality of different modes and configurationsto deliver a variety of ventilation therapies to a patent. The inventionalso relates to methods of operating and servicing such a ventilator.

A medical ventilator is a machine that is structured to deliver a gas,such as air, oxygen, or a combination thereof, to an airway of patientto augment or substitute the patient's own respiratory effort. It isgenerally known to operate a conventional medical ventilator in aparticular mode depending upon the specific ventilation therapy needs ofthe patient.

In a life support situation, where there is substantially no spontaneousrespiratory effort by the patient, a controlled mode of ventilation istypically provided, where the ventilator assumes full responsibility forventilating the patient. In this mode of ventilation, a controlledvolume of gas is delivered to the patient during each inspiratory phaseof the ventilatory cycle, and the trigger point (i.e., the transitionfrom the expiratory phase to the inspiratory phase of the ventilatorycycle) and cycle point (i.e., the transition from the inspiratory phaseto the expiratory phase of the ventilatory cycle) of the ventilator aretypically determined based on time.

Traditionally, ventilators used in life support situations employ whatis known as a dual-limb patient circuit, which has an inspiratory limbfor carrying gas to the patient, and an expiratory limb for carrying gasfrom the patient to an exhaust assembly. The exhaust assembly includes aselectively controllable valve or similar mechanism for activelycontrolling the discharge of the gas that has been expired from thepatient during the expiratory phase of the ventilatory cycle to theatmosphere. Such a configuration is commonly referred to as an “activeexhaust” or “active exhalation” configuration. Typically, theaforementioned controlled volume life support ventilation is invasive,meaning that the patient interface (e.g., without limitation,tracheostomy tube, endotracheal tube, etc.) which is employed tointerface the patient circuit to the airway of the user, is inserteddirectly into the patient's airway and is structured to remain there foran extended period of time.

In non-life support situations, where the patient exhibits some degreeof spontaneous respiratory effort, an assist mode or a support mode ofventilation is typically provided in which the ventilator augments orassists in the patient's own respiratory efforts, typically by providinga predetermined pressure to the airway of the patient. In this mode ofventilation, the pressure of the flow of gas is controlled. For example,in bi-level non-invasive ventilation, an inspiratory positive airwaypressure (IPAP) is delivered to the patient during the inspiratory phaseof each ventilatory cycle, and an expiratory positive airway pressure(EPAP), which is typically lower than the IPAP level, is delivered tothe patient during the expiratory phase of each ventilatory cycle.

Some ventilators that are adapted for used in non-life supportsituations employ what is known as a single-limb patient circuit; havingonly one limb that is used for carrying gas both to and from thepatient. Traditionally, such single-limb circuits employ a passiveexhalation device, often in the form of a hole or exhaust port in thelimb and/or the patient interface, to allow the patient's expired gas tobe passively vented to the atmosphere. Such a configuration is commonlyreferred to as a “passive exhaust” or “passive exhalation”configuration.

Additionally, unlike the aforementioned invasive patient interface(s)that are commonly associated with volume control ventilation, thepatient circuit for pressure support ventilation therapy is typicallynon-invasive. For example and without limitation, a nasal mask, nasaloral mask, full face mask, or a nasal canula, is temporarily employed bythe patient to receive the pressurized gas from the ventilator on anas-needed basis.

In view of the foregoing, it will be appreciated that the ventilatorsand associated ventilator hardware, and the associated methods ofemploying the same to administer ventilation therapy to the patient,have traditionally been significantly different for volume controlventilation operating modes than for pressure support operating modes.Moreover, known ventilators, ventilator hardware and/or associatedmethods for one of these two modes (e.g., pressure support) are oftennot compatible with ventilators, ventilator hardware and/or associatedmethods for the other modes (e.g., volume control).

Accordingly, it is an object of the present invention to provide aventilator that overcomes the shortcomings of conventional ventilator.This object is achieved according to one embodiment of the presentinvention by providing a ventilator that including a housing, an inletport, a flow generator structured to generate a flow of gas, and anoutlet port structured to discharge the flow of gas from the housing.The ventilator is capable of being operable among a plurality ofdifferent modes. In addition, the ventilator includes a porting systemhaving a plurality of sensors structured to monitor a number ofparameters with respect to the flow of gas, and a number of portingblocks. Each blocking port includes a removable routing elementstructured to be selectively coupled to the housing of the ventilator inorder to configure the sensors in one of a plurality of differentpredetermined configurations corresponding to a desired one of the modesof operation of the ventilator. A fastening mechanism fastens theremovable routing element to the housing of the ventilator.

In a further embodiment, this object is achieved by providing aventilator that includes a housing having an interior and an exterior,an inlet port extending from the exterior to the interior of thehousing, a flow generator disposed within the housing and that generatesa flow of gas, a outlet port adapted to discharge the flow of gas fromthe housing. A patient circuit including a patient interface and apassive exhalation device is in fluid communication with the outlet portto deliver the flow of gas to an airway of a patient. A controller isdisposed in the housing and being operatively coupled to the flowgenerator. The controller controls an inhalation volume of the flow ofgas, wherein when the patient exhales an exhalation gas during anexpiratory phase of the ventilatory cycle, the passive exhalation devicedischarges at least a portion of the exhalation gas to the atmosphere.

In a still further embodiment, this object is achieved by providing aventilator that includes a housing having an interior and an exterior,an inlet port extending from the exterior to the interior of thehousing, a flow generator disposed within the housing that generates aflow of gas, and an outlet port adapted to discharge the flow of gasfrom the housing to an airway of a patient during an inspiratory phaseof a ventilatory cycle. A controller disposed in the housing operate theventilator among a plurality of different modes, wherein the modesinclude a first mode for providing pressure support ventilation therapyto the patient and a second mode for providing volume controlventilation therapy to the patient.

In yet another embodiment, this object is achieved by providing aventilator that includes a housing having an interior and an exterior,an inlet port extending from the exterior to the interior of thehousing, a flow generator disposed within the ventilator that generatesa flow of gas, and an outlet port for discharging the flow of gas fromthe housing. The ventilator also includes an inlet airflow assemblyhaving a cover member selectively coupled to the housing of theventilator at or about the inlet port. The cover member has a firstside, a second side disposed opposite the first side, and an inletaperture extending through the cover member. The inlet aperturedelivering a gas to the inlet port of the ventilator. A number offiltering members are disposed between the first side of the covermember and the housing of the ventilator. In addition, a fasteningmechanism attaches the cover member to the housing of the ventilator,thereby securing the cover member and the number of filtering memberswith respect to the housing. The inlet airflow assembly is removablefrom the housing, without requiring the remainder of the ventilator tobe disassembled.

In another embodiment, this object is achieved by providing a ventilatorhaving a housing providing a first power connection being electricallyconnectable to an alternating current (AC) power source. The ventilatorincludes a second power connection being electrically connectable to alead acid battery. An internal rechargeable battery pack is alsodisposed within the interior of the housing. Finally, a detachablebattery pack is removably coupled to the exterior of the housing. Apower control mechanism controls the supply of power to the ventilatorfrom a corresponding at least one of the AC power source, the lead acidbattery, the internal rechargeable battery pack, and the detachablebattery pack.

These and other objects, features, and characteristics of the presentinvention, as well as the methods of operation and functions of therelated elements of structure and the combination of parts and economiesof manufacture, will become more apparent upon consideration of thefollowing description and the appended claims with reference to theaccompanying drawings, all of which form a part of this specification,wherein like reference numerals designate corresponding parts in thevarious FIGS. It is to be expressly understood, however, that thedrawings are for the purpose of illustration and description only andare not intended as a definition of the limits of the invention. As usedin the specification and in the claims, the singular form of “a”, “an”,and “the” include plural referents unless the context clearly dictatesotherwise.

FIG. 1 is front perspective view a medical ventilator in accordance withan embodiment of the invention;

FIG. 2 is a back elevation view of the medical ventilator of FIG. 1;

FIG. 3 is a partially exploded rear perspective view the medicalventilator of FIG. 1, showing a detachable battery pack and a portingsystem therefor;

FIG. 4 is a schematic view of a medical ventilator and componentstherefor arranged in a passive exhalation without proximal pressuresensing configuration;

FIG. 5 is a schematic view of the medical ventilator of FIG. 4, modifiedto show the medical ventilator and components therefor arranged in apassive exhalation with a proximal pressure sensing configuration;

FIG. 6 is a schematic view of the medical ventilator of FIG. 5, modifiedto show the medical ventilator and components therefor arranged in anactive exhalation configuration;

FIG. 7A is an perspective view of the porting block of the portingsystem of FIG. 3;

FIG. 7B is a sectional view take along line 7B-7B of FIG. 7A;

FIG. 8 is an perspective view of another porting block for the portingsystem of the medical ventilator;

FIG. 9 is an isometric view of another porting block for the portingsystem of the medical ventilator;

FIG. 10 is a partially exploded isometric view of the back of a medicalventilator and an intake airflow assembly therefor;

FIG. 11 is an exploded isometric view of the intake airflow assembly ofFIG. 10, also showing the flow generator of the medical ventilator;

FIG. 12 is a schematic view of a power supply system for a medicalventilator;

FIG. 13 is an isometric view of the detachable battery pack of FIG. 3;

FIG. 14 is a sectional view taken along line 14-14 of FIG. 3; and

FIG. 15 is a flow diagram for a method of supplying power to a medicalventilator.

Directional phrases used herein, such as, for example and withoutlimitation, top, bottom, left, right, upper, lower, front, back, andderivatives thereof, relate to the orientation of the elements shown inthe drawings and are not limiting upon the claims unless expresslyrecited therein.

As employed herein, the term “patient interface” refers to any known orsuitable mechanism for establishing fluid communication between theventilator and an airway of a patient and expressly includes, but is notlimited to, non-invasive patient interfaces, such as masks, nasalcanulas, combination nasal/oral masks, and removable mouth pieces, andinvasive patient interfaces, such as tracheal tubes and endotrachealtubes, as well as humidifiers, nebulizers and meter dose inhalers, whichcan be invasive or non-invasive.

As employed herein, the term “mode” refers to the manner in which theventilator is operated in order to provide a particular type ofventilation therapy, (e.g., without limitation, pressure supportventilation therapy; volume control ventilation therapy) to the patient.

As employed herein, the term “probe” refers to any known or suitablesensing element (e.g., without limitation, a conduit), which is incommunication with a sensor (e.g., without limitation, a machine flowsensor; a proximal pressure sensor; a monitor flow sensor), and isstructured to relay information concerning a parameter (e.g., withoutlimitation, pressure) to the sensor.

As employed herein, the term “interface mechanism” refers to any knownor suitable device (e.g., without limitation, connector, receptacle, orplug) for connecting the ventilator to an accessory (e.g., withoutlimitation, an oxygen blender, a humidifier, a pulse oximeter), device(e.g., without limitation, a printer), or communication or memory device(e.g., without limitation, the Internet; a hard drive disk, CD or othersuitable storage medium; a computer).

As employed herein, the terms “fastener” and “fastening mechanism” referto any known or suitable securing mechanism(s) for securing one part toanother part, and expressly include, but are not limited to, rivets,screws, bolts, combinations of bolts, washers and/or nuts, as well asintegral securing mechanisms such as, for example and withoutlimitation, molded tabs and resilient protrusions, which extend from onepart and engage another part to secure the parts together.

As employed herein, the statement that two or more parts are “coupled”together shall mean that the parts are joined together either directlyor joined through one or more intermediate parts.

As employed herein, the term “number” shall mean one or an integergreater than one (i.e., a plurality).

A. System Architecture

FIG. 1 shows an illustrative embodiment of a medical ventilator 2 inaccordance with an embodiment of the invention. As will be described ingreater detail hereinbelow, medical ventilator 2 (sometimes referred toherein simply as “the ventilator”) is capable of being selectivelyconfigured operate in a plurality of different modes, as defined herein,to provide ventilation therapy to a patient 170 (partially shown insimplified form in FIGS. 4, 5, and 6). It should be understood thatventilator 2 is shown and described herein for illustrative purposesonly, and that the features and methods described herein may beimplemented in other types of ventilators (not shown) having variousother capabilities and modes of operation.

Ventilator 2 includes a housing 4 having an interior 6, and an exterior8 with an exterior surface 10. In an exemplary embodiment, ventilator 2is designed to be portable and, therefore, includes a handle 11, whichis pivotably coupled to the top of the housing, in order to facilitatecarrying or moving of the ventilator. Handle 11, which is shown in thestowed position in FIG. 1, is also shown in the upright position inphantom line drawing in FIG. 3.

In the example of FIG. 1, ventilator 2 includes a user interface 300,which is disposed on exterior surface 10 at the front of ventilatorhousing 4. Among other features, user interface 300 includes a screen ordisplay 302, which is structured to display a number of parameters(e.g., without limitation, pressure, volume, flow rate) relating to theventilator and/or the patient 170 (FIGS. 4, 5 and 6). User interface 300also includes a plurality of input members 304, 306, 308, 310, and 312,which are manipulatable by the user, for example, in order to controlthe operation of the ventilator and/or to navigate among the parameters(not expressly shown) displayed on screen 302. For example and withoutlimitation, in one non-limiting example embodiment, input member 310comprises an ON/OFF button and input member 312 comprises a mode buttonfor switching among the various modes of operation of ventilator 2, oramong various displays viewable on screen 302 of user interface 300.Similarly, input members 304, 306, and 308 could, for example andwithout limitation, comprise buttons employable by the user to navigate,select and/or program various features of the ventilator via the userinterface.

It will, however, be appreciated that the particular arrangement of theuser interface 300 is not meant to be a limiting aspect of the presentinvention. Specifically, it will be understood that the ventilator 2could have any known or suitable alternative user interface with anysuitable configuration other than that which is shown and describedherein. For example, the present invention contemplated providing dials,knows, touch pads, roller balls, a mouse, or other input device, inaddition to or in place of input members 304, 306, 308, 310, and 312.Also, display 203 can be configured as a touch screen display so that itfunctions as an input device, in addition to or in place of inputmembers 304, 306, 308, 310, and 312. Also, the present inventioncontemplates operating ventilator 2 via a remote control, so that theinput members 304, 306, 308, 310, and 312 can be eliminated.

Ventilator 2 also preferably has a variety of different interfacemechanisms 320, 322, 324, 326, 328, and 330 as defined herein. Forexample and without limitation, ventilator 2 may include a receptacle320, such as the one disposed toward the bottom of ventilator housing 4in the example shown in FIG. 1. In one non-limiting embodiment of theinvention, such receptacle 320 could be adapted to electronicallyconnect ventilator 2 to a power source (see, for example, alternatingcurrent (AC) power source 402 and lead acid battery power source 406,schematically shown in FIG. 12 and described in greater detailhereinbelow). Any known or suitable type, number, and/or configurationof interface mechanisms such as, for example and without limitation, thefive additional interface mechanisms 322, 324, 326, 328, and 330 shownin FIGS. 2 and 3, can be provided within the scope of the invention.

It will also be appreciated that such interface mechanisms (e.g.,without limitation, receptacles; connectors) can be employed for anyknown or suitable purpose such as, for example and without limitation,to connect ventilator 2 to the Internet (by, for example, an Ethernetnetwork), to a separate device such as, for example and withoutlimitation, a printer (not shown) or computer (not shown), or to anysuitable ventilator accessory such as an accessory medical device like apulse oximeter or a carbon dioxide monitor, or an alternative gas source(see, for example, optional oxygen source 31, schematically shown inFIGS. 4, 5 and 6 and described hereinbelow).

FIGS. 4, 5 and 6, respectively, show three illustrative exampleconfigurations of ventilator 2, in simplified form. Specifically, FIG. 4shows the components of the ventilator configured to provide passiveexhalation without proximal pressure sensing. FIG. 5 shows thecomponents of the ventilator configured for providing passive exhalationwith proximal pressure sensing. In addition, FIG. 6 shows the componentsof the ventilator configured to provide active exhalation.

More specifically, as schematically shown in FIG. 4, ventilator 2includes a flow generator 36, which is structured to generate a flow ofgas 38, for example, from air 38′ (ambient atmosphere) that enters theventilator housing 4 through an inlet port 30 and/or a mixture of air38′ with a suitable supplemental gas, such as oxygen. The supplementaloxygen can be provided from one of the aforementioned ventilatoraccessories, such as an oxygen source 31, shown in simplified form inFIGS. 4, 5 and 6. In one non-limiting embodiment of the invention,oxygen source 31, which is optional, comprises a low-flow (e.g., withoutlimitation about 0-50 psi and about 15 liters per minute (LPM) oxygenblender, which is connected to ventilator 2 via one of theaforementioned interface mechanisms such as, for example and withoutlimitation, interface mechanism 328, which in the example schematicallyshown and described herein is a quick-connect valve fitting.

In the illustrated exemplary embodiment, ventilator 2 also includes anair inlet filter 32 for filtering ambient air 38′ entering ventilatorhousing 4. As will be discussed in greater detail hereinbelow, ambientair 38′ and/or the gas from the optional supplemental oxygen source 31is preferably directed through an inlet airflow assembly 200, prior toreaching the flow generator 36. The example flow generator 36 is amicro-turbine comprising a blower assembly having a brushless directcurrent (DC) motor (not shown) with an impeller design (partially shownin FIG. 11) for generating the desired pressures and flows of gas 38,which are required by ventilator 2. In one non-limiting embodiment, themicro-turbine 36 is operable at a speed of about 3,000-42,000revolutions per minute (rpm). It will, however, be appreciated that flowgenerator 36 could be any known or suitable device structured to createthe flow of gas 38 at a pressure greater than ambient atmosphere suchas, for example and without limitation, a compressor, a fan, animpeller, a blower, a piston, or bellows.

Continuing to refer to FIG. 4, the flow of gas 38 exiting flow generator36 passes through an optional flow screen (filter) 40, which is in fluidcommunication with a first flow element 42 disposed in housing 4.Because first flow element 42 is disposed within the ventilator, it isalso referred to herein as machine flow element 42. Machine flow element42, which is positioned proximate the outlet of flow generator 36 may,for example and without limitation, be a mechanical element, such as anorifice or valve. Machine flow element 42 is designed to produce apressure drop when the flow of gas 38 passes through it. It will beunderstood, however, that any known or suitable alternative numberand/or configuration of flow elements could be employed to provide anysuitable flow of gas 38 for ventilator 2, without departing from thescope of the invention.

A first (machine) flow sensor 46 is provided in tandem with machine flowelement 42, in order to measure the flow rate of gas flow 38 based onthe pressure drop across the machine flow element. In addition, a secondflow sensor 50, which in the example shown and described herein is adifferential pressure sensor, is also provided to measure the flow rateof gas 38 by measuring the pressure drop across machine flow element 42via lines 52 and 54. Second flow sensor 50 thus monitors the volumetricflow of gas 38 in a redundant manner with that done by first flow sensor46. Second flow sensor 50 is also referred to herein as monitor flowsensor 50. It will be appreciated that flow sensors 46 and 50, and othersensors within the ventilator 2 are configurable and reconfigurable to aplurality of different configurations corresponding to the variousoperating modes of the ventilator, as will be described hereinbelow withrespect to the examples of FIGS. 5 and 6. It can be further appreciatedthat only the ventilator need not have both flow sensors. In addition,the present invention even further contemplates eliminating one or bothflow sensors in favor of measuring the flow rate, or a parameterindicative of the flow rate, using other techniques, such as based onthe power provided to flow generator, the speed of the flow generator,etc.

A control machine pressure sensor 86 is operatively coupled to aninternal conduit 143 that supplies the flow of gas 38 from flowgenerator 36 through an outlet port 44 to an external conduit 144, andfinally to patient interface 146. The example control machine pressuresensor 86 is connected to internal conduit 143 through an auto zerovalve 87. Sensor 86 is a static pressure sensor used to monitor thepressure at or about outlet port 44 of ventilator 2. In addition, amonitor machine pressure sensor 88 is operatively coupled to internalconduit 143. Monitor machine pressure sensor 88 is also a staticpressure sensor used to monitor the pressure at or about outlet port 44,in a redundant fashion. Other sensors suitable for use with ventilator 2include, but are not limited to, temperature sensors 51 and 53, whichare operatively coupled to the internal conduit 143 and are employed tomonitor the temperature of the flow of gas 38 exiting flow generator 36,and a barometric pressure sensor 55 for measuring atmospheric pressure,for example, to allow for altitude adjustment of the calculatedvolumetric flow.

Although it is not employed in the passive exhalation without proximalpressure sensing configuration, which is shown in the example of FIG. 4,ventilator 2 also includes an active exhalation control assembly 90,which is employed when the ventilator is configured in the activeexhalation configuration mode, as shown, for example, in FIG. 6.Finally, ventilator 2 includes a controller 98, which is schematicallyshown in FIGS. 4, 5 and 6. Controller 98 is electronically connected to,and is adapted to communicate with, each of the aforementionedcomponents in order to selectively control the ventilator.

In the example of FIG. 4, ventilator 2 has one single external conduit144 that interconnects outlet port 44 of the ventilator and patientinterface 146. Accordingly, patient circuit 150 of ventilator 2 is asingle-limb circuit, wherein the single external conduit 144 bothdelivers the flow of gas 38 from outlet port 44 to the patient interface146 and ultimately to an airway 160 of patient 170 (partially shown insimplified form in FIGS. 4, 5, and 6), and carries exhalation gas 38″,which is exhaled by patient 170 during the expiratory phase of theventilatory cycle. Single-limb patient circuit 150 of FIG. 4 includes apassive exhalation device 152 (e.g. without limitation, a valve,orifice, port, or other vent arrangement) for venting (i.e.,discharging) exhalation gas 38″ to the atmosphere.

Although the patient interface 146 which is shown in the examplesdescribed herein is, for simplicity of illustration, a non-invasive mask146, it will be appreciated that any known or suitable alternativepatient interface, as defined herein, could be employed in any suitableconfiguration with the patient circuit 150 (FIG. 4), 150′ (FIG. 5), 150″(FIG. 6). It will also be appreciated that the passive exhalation device152 may be coupled to patient circuit 150, patient interface 146, orboth.

Referring now to FIG. 5, the components of ventilator 2 areschematically shown as configured to provide passive exhalation withproximal pressure sensing. In this configuration, the ventilatorcomponents and the predetermined sensor configuration are largely thesame as for the passive exhalation without proximal pressureconfiguration, previously described with respect to FIG. 4. However, inaddition, a proximal pressure sensor 48 provided in housing 4 isconfigured to be in fluid communication with single external conduit144′ of single-limb patient circuit 150′, via a probe 57 (e.g., aconduit), as defined herein, which is disposed proximate patientinterface 146 that connects to line 56.

FIG. 6 shows a schematic illustration of ventilator 2 and componentstherefor in an active exhalation configuration. In such a configuration,ventilator 2 includes an alternate single-limb patient circuit 150″ influid communication with the outlet port 44. Specifically, in additionto an external conduit 144″, the single-limb patient circuit 150″ alsoincludes a proximal flow element 154 and an active exhalation device 156(e.g., without limitation, valve). Proximal flow element 154 is amechanical element positioned in the patient circuit generally proximateto patient interface 146″, and is designed to produce a pressure dropwhen the flow of gas 38 and/or the exhalation gas 38″ passes through it.

In an exemplary embodiment, active exhalation device 156 is aproportionally controlled pressure relief valve disposed in thesingle-limb patient circuit 150″ and structured to providelow-resistance for enabling carbon dioxide flushing of the exhalationgas 38″ during the expiratory phase of the ventilatory cycle. It will beappreciated that the active exhalation device 156 may be coupled topatient circuit 150″, patient interface 146″, or both. Active exhalationdevice 156 is structured to provide minimal exhalation resistance inorder to meet anti-asphyxia requirements in the event of a loss oftherapy (e.g., without limitation, a ventilator failure). Specifically,active exhalation device 156 includes an anti-asphyxia device 158 (shownin simplified form in FIG. 6) to meet such requirements. In onenon-limiting embodiment, the anti-asphyxia device is a flapper valve 158made, for example and without limitation, from rubber or anothersuitable material, which is structured to deflect, in the event of afailure or partial failure of ventilator 2, to uncover a correspondingaperture (not expressly shown) of the active exhalation device 156. Suchaperture is in fluid communication with the atmosphere. Accordingly,flapper valve 158 ensures that patient 170 can, at a minimum, have thepotential to inspire ambient air in the event of such failure of theventilator 2.

In the example of FIG. 6, controller 98 is operatively coupled to theactive exhalation control assembly 90 and, therefore, to activeexhalation device 156. The active exhalation control assembly 90 is apressure unit that regulates a diaphragm 157 (shown in simplified formin FIG. 6) of active exhalation device 156, in order to control biasflow as patient 170 exhales during the expiratory phase of theventilatory cycle. The example active exhalation control assembly 90includes a dump valve 91 structured to quickly reduce pilot pressurefrom diaphragm 157, thereby allowing it to fully open as patientexhalation is initiated, and a proportional valve 92 that, incombination with an orifice 93 provided between the two valves 91,92,controls the bias flow.

It can be appreciated that ventilator 2 is a small, lightweight,versatile ventilator that can be operated in a single-limb or dual-limbconfiguration and can provide both a pressure support therapy or avolume controlled therapy. Moreover, both the pressure support therapyor a volume based therapy can be delivered in a non-invasive system,e.g., a single limb system with intentional gas leaks such as thatthrough the exhalation valve.

Table 1 below lists the specifications for an exemplary embodiment ofthe ventilator of the present invention.

TABLE 1 Specification Value Weight Size 4.5″ × 6.88″ × 9.5″ VentilationModes A/C, SIMV, CPAP, S, S/T, T, PC, Flex Tidal Volume (ml)  50-2000Rate (bpm)  0-60 Peak Flow (lpm)  3-150 I-Time (second) 0.2-5.0 VolumeTrigger Sensitivity (cmH₂O pressure, flow) E-Cycle (% peak flow)Pressure Support (cmH₂O)  0-50 Rise Time (second) 0.1-0.6 EPAP/PEEP(cmH₂O)  4-46 Internal Battery Runtime (hours) 4.0 Detachable Battery4.0 Runtime (hours) Internal Battery Charge Time 8 hours or lessB. Porting System

It will be appreciated that the disclosed ventilator is operable among aplurality of different modes of operation including, but not limited to,a first mode for providing pressure support ventilation therapy topatient 170, and a second mode for providing volume control ventilationtherapy to the patient. Furthermore, within such modes, ventilator 2 canhave any suitable exhalation configuration such as, for example andwithout limitation, the aforementioned passive exhalation withoutproximal pressure sensing configuration of FIG. 4, the passiveexhalation with proximal pressure sensing configuration of FIG. 5, andthe active exhalation configuration of FIG. 6.

Switching ventilator 2 from one of these modes and/or configurations toanother requires certain features of the ventilator 2 such as, forexample and without limitation, the sensors and/or the patient circuitto be replaced and/or reconfigured. Traditionally, with a conventionalventilator, this has been a time-consuming endeavor that required asignificant amount of disassembly and/or manipulation of the ventilator,or the use of a different ventilator altogether. This is because, priorto ventilator 2 of the present invention, all of the foregoing operatingmodes and configurations have not been available in one singleventilator device. As will now be discussed, one manner by which thedisclosed ventilator overcomes these disadvantages is by providing aporting system 100 having a plurality of interchangeable porting blocks102 (FIGS. 3, 7A, and 7B), 102′ (FIG. 8), and 102″ (FIG. 9) that enableventilator 2 to be quickly and easily configured and/or reconfigured tothe desired mode.

Specifically, porting system 100 includes the aforementioned sensors(e.g., without limitation, machine flow sensors 46, proximal pressuresensor 48, monitor flow sensor 50) and a plurality of probes (e.g.,without limitation, conduits) therefor. For example, the exemplarymachine flow sensor 46 includes a first machine flow probe 52 and asecond machine flow probe 54, the proximal pressure sensor 48 includesat least one proximal pressure probe 56, and the monitor flow sensor 50includes a first monitor flow probe 60 and a second monitor flow probe62. Probes 52, 54, 56, 60, 62 are accessible at one common location onexterior surface 10 of ventilator housing 4. Each porting block 102(FIGS. 3, 4, 7A and 7B), 102′ (FIGS. 5 and 8), and 102″ (FIGS. 6 and 9)includes a removable routing element 103 (FIGS. 3, 4, 7A, and 7B), 103′(FIG. 5), and 103″ (FIG. 6) structured to be selectively coupled toventilator housing 4 at or about the aforementioned common location, inorder to configure probes 52, 54, 56, 57, 58, 59, 60, 62, 63, and 65(all shown in FIG. 6) and thus the corresponding sensors 46, 48, 50,without requiring the ventilator 2 to be disassembled. This aspect ofthe invention will be further appreciated with reference to FIG. 3,wherein removable routing element 103 of porting block 102 is shownexploded away from ventilator housing 4.

A fastening mechanism 116 of porting system 100 is structured to fastenremovable routing element 103 to housing 4, as shown in FIG. 2. Theexample fastening mechanism 116, which is also shown in FIG. 3, is asingle fastener 118 structured to extend through a hole 119 of theremovable routing element 103. As shown in FIG. 3, and also in FIGS. 7Aand 7B, removable routing element 103 includes a first side 120, asecond side 122 disposed opposite the first side, first and secondopposing ends 124 and 126, and a plurality of passageways 104, 106, 108,110, and 112 (FIG. 7B; see also passageways 104, 106, 108, 110, 112, and114 schematically shown in FIG. 4), which extend from the first side 120toward the second side 122. As employed herein, the term “passageway”refers to any known or suitable hole, throughway, conduit, or pathwaythat extends through at least a portion of an object, and expresslyincludes both active passageways, which are structured to allow for thepassage of a fluid (e.g., gas) therethrough, and inactive passageways(i.e., closed passageways), which are structured to resist the passageof the fluid (e.g., gas) therethrough. When removable routing element103 of the selected porting block (e.g., 102) is coupled to ventilatorhousing 4, passageways 104, 106, 108, 110, 112, and/or 114 thereofcooperate with probes 52, 54, 56, 60, 62, and/or 63 in order toestablish the desired predetermined sensor configuration correspondingto the selected mode of operation of the ventilator.

For economy of disclosure, operation of only one of the porting blocks102, will be described in detail. It will, however, be appreciated thatthe other interchangeable porting blocks (e.g., without limitation,porting blocks 102′ and 102″) of porting system 100 are employed insubstantially the same manner. Referring again to FIG. 3, exteriorsurface 10 of ventilator housing 4 includes a recess 64 structured toreceive removable routing element 103 of porting block 102. Thus, asshown in FIG. 2, second side 122 of removable routing element 103 issubstantially flush with respect to exterior surface 10 of ventilatorhousing 4, adjacent recess 64, when removable routing element 103 iscorrectly inserted into recess 64. Hence, the interchangeable portingblock design of the invention does not create undesirable protrusionsthat extend outwardly from ventilator housing 4.

In the example of FIG. 3, recess 64 includes first and second apertures66 and 68 structured to receive first and second protrusions 132 and134, respectively, which extend outwardly from first side 120 ofremovable routing element 103 (FIGS. 3, 7A and 7B). As shown in FIG. 7Aand the sectional view of FIG. 7B, protrusions 132 and 134 preferablyinclude seals 136 and 140, respectively. Seals 136 and 140 (see alsoO-ring seals 138 and 142) may be made from any known or suitablematerial such as, for example and without limitation, silicone rubber,and are structured to be respectively disposed on a correspondingportion of the protrusions 132, 134, 137, and 141 (best shown in FIG.7B) in order to resist the unintentional leaking of the flow of gas 38(FIGS. 4, 5 and 6) from between removable routing element 103 andventilator housing 4. Removable routing element 103 in the example ofFIGS. 7A and 7B includes nipples 137 and 141 extending outwardly fromprotrusions 132 and 134, respectively, and the seals include elongatedseals 136 and 140 disposed in corresponding grooves of the protrusions132 and 134, respectively, and O-ring seals 138 and 142 disposed incorresponding grooves of the nipples 137 and 141, respectively.

Removable routing element 103 also includes a finger tab 130 disposedbetween first and second ends 124 and 126 of the removable routingelement 103, at or about second side 122 thereof. Finger tab 130 isstructured to facilitate the removal of removable routing element 103from recess 64 of the ventilator housing, for example, when it isdesired to replace it with a different one of the removable routingelements 103′ (FIGS. 5 and 8) or 103″ (FIGS. 6 and 9), in order tochange the configuration of the sensors of ventilator 2 for operation ina different mode. It will, however, be appreciated that any suitablealternative mechanism, other than the exemplary finger tab 130, could beemployed in any suitable arrangement to facilitate the removal ofremovable routing element 103. It will also be appreciated thatremovable routing element 103 may have any known or suitable alternativeconfiguration, without departing from the scope of the invention.

For example, FIGS. 8 and 9 show two non-limiting illustrativeembodiments of different porting blocks 102′ and 102″, respectively, inaccordance with the invention. As will be discussed, porting block 102′of FIG. 8 includes a removable routing element 103′ structured toestablish the predetermined sensor configuration schematically shown inFIG. 5, and porting block 102″ of FIG. 9 includes a removal routingelement 103″ structured to establish the predetermined sensorconfiguration schematically shown in FIG. 6. Specifically, similar toporting block 102 of FIGS. 3, 4, 7A, and 7B, removable routing element103′ of porting block 102′ has first and second protrusions 132′ and134′ with first and second nipples 137′ and 141′, respectively.

Although they are not shown in FIG. 8, the removable routing element103′ is also contemplated as including seals such as those previouslydiscussed with respect to FIGS. 7A and 7B. As will be discussedhereinbelow, the primary distinction of removable routing element 103′is with regard to the configuration of its passageways (see, forexample, passageways 104′, 106′, 108′, 110′, 112′, and 114′schematically shown in FIG. 5). One passageways 108′ is structured toconnect proximal flow sensor 48 to the patient circuit 150′, as shown inFIG. 5. This passageway 108′ extends through a port 109′, which extendsoutwardly from the exterior surface of the removable routing element103′, as shown.

As will be discussed with respect to FIG. 6, passageways 104″, 106″,108″, 110″, 112″, and 114″ (shown schematically in FIG. 6) of removablerouting element 103″ of FIG. 9 differ from those of removable routingelement 103′ (FIGS. 5 and 8) and removable routing element 103 (FIGS. 3,4, 7A and 7B) and are thereby structured to establish the sensorconfiguration schematically illustrated in FIG. 6. Specifically, asshown in FIG. 9, removable routing element 103″ includes first andsecond protrusions 132″ and 134″. First protrusion 132″ includes onesingle nipple 137″, and the second protrusion 134″ includes threenipples 141″, 145″, and 147″. In an exemplary embodiment, protrusions132″ and 134″ and nipples 141″, 145″, and 147″ include suitable seals(not shown in FIG. 9 for simplicity of illustration) such as thosepreviously discussed with respect to FIGS. 7A and 7B. First, second andthird passageways 104″,106″, and 108″ of removable routing element 103″extend through corresponding first, second, and third ports 105″, 107″,and 111″, respectively, of removable routing element 103″ to provide thedesired probe/sensor connections.

In addition to the fact that porting blocks 102 (FIGS. 3, 4, 7A and 7B),102′ (FIGS. 5 and 8), and 102″ (FIGS. 6 and 9) of porting system 100 cancomprise any suitable configuration other than the three which are shownand described herein, it will be appreciated that they could also bemade from any suitable material and by any suitable process or method.In one non-limiting example, interchangeable porting blocks 102,102′,102″ are single piece molded plastic components and, therefore, arerelatively easy and inexpensive to manufacture.

Referring again to FIG. 4, the predetermined configuration of thesensors (e.g., without limitation, machine flow sensor 46, proximalpressure sensor 48, and monitor flow sensor 50) for the passiveexhalation without proximal pressure sensing configuration and, inparticular, the use of the removable routing element 103 to establishsuch configuration, will now be discussed. Specifically, in operation,when a determination is made to operate ventilator 2 in accordance witha particular mode and/or exhalation configuration, the patient circuit(e.g., without limitation, single-limb patient circuit 150) thatcorresponds to that mode and/or configuration is selected and coupled tooutlet port 44 of ventilator 2. Alternatively, patient circuit 150 canbe configured or reconfigured as desired, for example by exchanging oneexhalation device (e.g., a passive exhalation device 152) with anotherexhalation device (e.g., a different passive exhalation device; anactive exhalation device 156 as shown, for example, in FIG. 6) and/or byattaching or changing patient interface 146. In other words, singleoutside conduit 144 of patient circuit 150 could remain attached tooutlet port 44 of ventilator 2, with the exhalation device 156 and/orthe patient interface 146 being selectively coupled to the conduit 144,for example by one or more quick-change fittings (e.g., withoutlimitation, a slip fitting) (not expressly shown). Thus, patientcircuits that are both removable and replaceable or interchangeable intheir entirety, and patient circuits that are selectively configurableand/or reconfigurable, in part, are within the scope of the invention.

After selecting or configuring the patient circuit 150 (FIG. 4), 150′(FIG. 5), or 150″(FIG. 6), the corresponding porting block 102 (FIGS. 3,4, 7A and 7B), 102′ (FIGS. 5 and 8), or 102″(FIGS. 6 and 9) is thenselected and attached to ventilator housing 4 (best shown in FIG. 2). Aspreviously noted, to establish the various predetermined sensorconfigurations, each of the removable routing elements 103 (FIGS. 3, 4,7A, 7B), 103′ (FIGS. 5 and 8) and 103″ (FIGS. 6 and 9) has a differentarrangement of passageways, which are structured to selectivelycooperate with the sensor probes in a predetermined manner.Specifically, in the example of FIG. 4, the removable routing element103 includes first, second, third, fourth, and fifth active passageways,104, 106, 108, 110, and 112, and one inactive passageway 114. Firstactive passageway 104 cooperates with second active passageway 106 inorder to connect first machine flow probe 52 to first monitor flow probe60. The third active passageway connects the proximal pressure sensor 48to the ambient atmosphere, for example, via a single proximal pressureprobe 56. Fourth and fifth active passageways 110, 112 cooperate withone another to connect second machine flow probe 54 to the secondmonitor flow probe 62, as shown. Finally, because the active exhalationcontrol assembly 90 is not employed in the passive exhalation withoutproximal pressure sensing configuration of FIG. 4, active exhalationcontrol probe 63 is connected to passageway 114, which is inactive(blocked).

Accordingly, it will be appreciated that all of the sensors areconfigurable to the desired predetermined configuration corresponding tothe selected mode of operation of ventilator 2, merely by attaching theappropriate interchangeable porting block (e.g., without limitation,102) to ventilator housing 4. It will, however, be appreciated that theexact arrangement of passageways of the removable routing elements 103(FIGS. 3, 4, 7A and 7B), 103′ (FIGS. 5 and 8), and 103″ (FIGS. 6 and 9)of the porting blocks 102 (FIGS. 3, 4, 7A and 7B), 102′ (FIGS. 5 and 8),and 102″ (FIGS. 6 and 9) is not meant to be a limiting aspect of theinvention. The porting system of the present invention allows the sameventilator sensors to be reconfigured quickly and easily by simplyinterchanging porting blocks 102 (FIGS. 3, 4, 7A and 7B), 102′ (FIGS. 5and 8), 102″ (FIGS. 6 and 9), i.e., without having to add or removeother sensing elements.

As shown in FIG. 5, and as previously noted, the components ofventilator 2 are arranged substantially similarly for the passiveexhalation with proximal pressure sensing configuration as for thepassive exhalation without proximal pressure sensing configurationdiscussed with respect to FIG. 4. The primary difference is theinclusion of a second proximal pressure probe 57, which is in fluidcommunication with the external conduit 144 of patient circuit 150′,proximate patient interface 146. Removable routing element 103′ ofsecond interchangeable porting block 102′ is structured to accommodatethis proximal pressure probe 57. Specifically, similar to removablerouting element 103, removable routing element 103′ includes first,second, third, fourth, and fifth active passageways 104′, 106′, 108′,110′, and 112′, and one inactive passageway 114′. The first and secondactive passageways 104′ and 106′ cooperate in order to connect firstmachine flow probe 52 to first monitor flow probe 60. However, unlikethird passageway 108 of removable routing element 103, which connectedproximal pressure probe 56 to the atmosphere, third passageway 108′ ofremovable routing element 103′ connects first proximal pressure probe 56to second proximal pressure probe 57, as shown. Fourth and fifth activepassageways 110′ and 112′ connect second machine flow probe 54 andsecond monitor flow probe 62, and active exhalation probe 63 isconnected to inactive passageway 114′.

Referring now to FIG. 6, when ventilator 2 and components therefor areconfigured for active exhalation, single-limb patient circuit 150″additionally includes the aforementioned proximal flow element 154 andactive exhalation device 156. Accordingly, a number of additional probessuch as, for example and without limitation, third and fourth proximalpressure probes 58 and 59 and an active exhalation device probe 65, arerequired. The configuration of these and other probes is established bythird removable routing element 103″ of interchangeable porting block102″ and, in particular, first, second, third, and fourth activepassageways 104″, 106″, 108″, and 110″ and first and second inactivepassageways 112″ and 114″ thereof.

First active passageway 104″ connects first monitor flow probe 60 tosecond proximal pressure probe 57, second active passageway 106″connects first proximal pressure probe 56 to fourth proximal pressureprobe 59, and third active passageway 108″ connects second monitor flowprobe 62 to third proximal pressure probe 58. In this manner, proximalpressure probes 57 and 58 communicate with sensor 50 to monitor the flowof gas 38, 38″ on opposing sides of the proximal flow element 154.Fourth active passageway 110″ connects first active exhalation controlprobe 63 to active exhalation device probe 65. Thus, in thisconfiguration, active exhalation control assembly 90 is activelyemployed via controller 98 to monitor and control active exhalationdevice 156. Machine flow sensor 46 and first and second machine flowprobes 52, 54 are not required in this configuration and, therefore, arecoupled to first and second inactive passageways 112″ and 114″,respectively.

In view of the foregoing, it will be appreciated that the inventionenables a single ventilator 2 to be quickly and easily configured orreconfigured to provide various types of ventilation therapy, withoutrequiring the ventilator to be disassembled or replaced. Particularlyunique is the ability of ventilator 2 to provide volume controlventilation therapy (also referred to volume ventilation) to patient 170using the aforementioned passive exhalation device 152 (e.g., withoutlimitation, passive exhalation valve, orifice). Effective patientventilation using this combination was previously thought to besubstantially impossible.

Specifically, it is somewhat counterintuitive to allow for the passiveescape of gas 38″ to the atmosphere when it is vitally important toaccurately maintain a desired inhalation volume of gas 38 for thepatient as is often the case in volume control, life support situations.Accordingly, known volume control (i.e., life support) ventilationsystems (not shown) have traditionally required an active exhalationdevice which serves as part of a dual-limb patient circuit (i.e., thepatient circuit includes at least two external conduits, one for patientinhalation during the inspiratory phase of the ventilatory cycle and onefor patient exhalation during the expiratory phase of the ventilatorycycle). This tended to result in a ventilator design that was larger andmore complex than desired. As such, the ventilators were generally notconducive for use outside of a hospital, designated care center or otherfacility where the ventilator could be closely monitored and maintainedby a doctor, medical specialist, or trained personnel.

The ability of the ventilator of the present invention to provide volumecontrol ventilation therapy using passive exhalation overcomes thesedisadvantages, and others, by providing a single substantially mobile,lightweight ventilator 2, which enables the patient to move relativelyeasily from one location to another while continuing to receive theappropriate ventilation therapy. Accordingly, the disclosed ventilatoraffords the patient the opportunity to maintain a relatively activelifestyle.

More specifically, as previously discussed and referring, for example toFIG. 5, patient circuit 150′ of the example ventilator is preferably asingle-limb circuit 150′ including a single external conduit 144′,wherein the single-limb circuit may comprise a separate, self-containedassembly that is selectively connectable to ventilator 2 at outlet port44 thereof, or it may be selectively configurable with components suchas patient interface 146 and passive exhalation device 152 beingselectively connectable to single conduit 144′. In any event, singleconduit 144′ interconnects outlet port 44 of ventilator 2 and patientinterface 146. Passive exhalation device 152 is coupled to singleconduit 144′ proximate patient interface 146. When operating in acontrolled volume (volume ventilation) mode, controller 98 of ventilator2, which is operatively coupled to flow generator 36, is adapted toselectively control flow generator 36 to generate the flow of gas 38having an inhalation volume, also referred to as an inspiratory tidalvolume. The present invention also contemplates providing a volumeventilation in which the inspiratory flow profile is provided over apredetermined inspiratory time.

Single-limb patient circuit 150′ delivers the flow of gas 38 having theinhalation volume to airway 160 of patient 170 during the inspiratoryphase of the ventilatory cycle. In the example shown and describedherein, both the inhalation volume of the flow of gas 38 and exhalationgas 38″ are transported within the single conduit 144′ of thesingle-limb patient circuit 150′. It will be appreciated that a functionof passive exhalation device 152 is to flush carbon dioxide, which ispresent in exhalation gas 38″ exhaled by the patient, to the atmosphere.Subsequently, a fresh inhalation volume of a flow of gas 38 may bedelivered to the patient during the inspiratory phase of the nextventilation cycle.

It will be appreciated that the particular inhalation volume, or volumeventilation, prescribed for the patient is dependent on a variety ofdifferent factors including, but not limited to, the type of diseasefrom which the patient suffers, and the stage of progression of thedisease. In one non-limiting embodiment, ventilator 2 and, inparticular, controller 98 therefor, is adapted to selectively adjustflow generator 36, as necessary, to cause the flow of gas 38 to have thedesire inhalation volume, which is delivered to the patient during theinspiratory phase of the ventilatory cycle. This can be doneautomatically. Alternatively, ventilator 2 can be programmed using theaforementioned user interface 300, either by the patient himself/herselfor preferably by the doctor or caretaker. During the expiratory phase ofthe ventilatory cycle, at least a portion of the exhalation gas 38″,which is exhaled by the patient 170, is discharged to the atmosphere bypassive exhalation device 152. Accordingly, among other benefits,ventilator 2 provides effective volume control ventilation therapy,using passive exhalation such that neither the aforementioneddouble-limb patient circuit (not shown) nor the active exhalation deviceof known volume control ventilation systems (not shown) is required.

Controller 98 of ventilator 2 is preferably adapted to also provide leakcompensation. For example and without limitation, controller 98 may beadapted to execute a suitable leak compensation routine in order todetect a leak in the patient circuit 150′ and, responsive to detectingthe leak, make an appropriate adjustment with respect to the operationof the ventilator 2. One non-limiting example of a suitable leakcompensation routine is the Autotrack® software program, which iscommercially available from the assignee of the present invention.Examples of leak estimation/compensation techniques are provided in U.S.Pat. Nos. 5,148,802; 5,313,937; 5,433,193; 5,632,269; 5,803,065;6,029,664; 6,626,175; 6,360,741; 6,920,875; 6,948,497; and 7,100,607,the contents of which are incorporated herein by reference.

Alternatively, the present invention contemplates providing aknown/intended leak or a fixed leak device or exhaust port that has aknown leak rate to pressure relationship. This relationship can be usedto determine the leak rate for any given pressure.

Additionally, the present invention contemplates providing leakcompensation for unknown (unintended) leaks, such as leaks attributed tothe patient-to-ventilator circuit interface, leaks at the cuff, mouth,mask, etc. These unknown/unintended leaks are compensated for using adifferent programmed response than known leaks, i.e., leaks assigned tothe known or fixed (intended) leak device. This different programmedresponse can include (w/o limitation) leak limits, assumed pressure toleak relationships, and single or multiple time constants that areseparate and distinct from the relationships employed to model the knownor intended leak. This programmed response can be used to adjust theflow from the ventilator to ensure that the patient receives theprescribed tidal volume in the event of certain anticipatedphysiological or use case changes in the patient to ventilator circuitinterface.

In general, responsive to detecting or estimating a leak (intended,unintended, or both) of the flow of gas 38, controller 98 is adapted toselectively adjust flow generator 36 to cause the flow of gas to havethe desired inhalation volume, which is delivered to the patient duringthe inspiratory phase of the ventilatory cycle.

The expiratory phase of the ventilatory cycle has a tidal volume. Atleast some of the aforementioned sensors such as, for example, proximalsensor 48, can be employed in fluid communication with the patientcircuit (see, for example, patient circuit 150′ of FIG. 5), proximatepassive exhalation device 152, to determine the tidal volume of theexhalation gas 38″. Responsive to determining the tidal volume,ventilator controller 98 selectively adjusts flow generator 36 togenerate a flow of gas 38 having a desired inhalation volume, which isto be delivered to patient 170 during the inspiratory phase of the nextventilatory cycle.

Among other benefits, the adaptability of ventilator 2 enables the sameventilator to be employed throughout the progression of the patient'sdisease. For example, in one non-limiting circumstance, patient 170might progress from a condition that initially requires onlyintermittent pressure support ventilation therapy to eventuallyrequiring substantially constant volume control ventilation therapy.Such a progression may occur relatively slowly over an extended periodof time. Accordingly, a combination of ventilation therapies may berequired throughout the disease progression. The disclosed ventilator iswell suited to accommodate such circumstances and to meet theventilation needs of such a patient, regardless of what those needs maybe and how they may change.

Specifically, in one non-limiting embodiment, ventilator controller 98is adapted to selectively switch ventilator 2 among the volume controland pressure support modes. Additionally, if necessary, patient circuit(e.g., 150 (FIG. 4), 150′(FIG. 5), or 150″(FIG. 6)) can relativelyquickly and easily be exchanged (i.e., replaced) or reconfigured toprovide either passive exhalation, for example, as shown in FIGS. 4 and5, or active exhalation, for example, as shown in FIG. 6. Additionally,various patient interfaces 146 can be selectively employed, asnecessary, without requiring significant adjustment or replacement ofthe ventilator 2.

C. Inlet Airflow Assembly

FIG. 10 shows an inlet airflow assembly 200 for ventilator 2. Amongother benefits, inlet airflow assembly 200 is of a modular design and isselectively removable from ventilator housing 4 without requiring theremainder of ventilator 2 to be disassembled. Accordingly, the remainderof the ventilator can be relatively quickly, easily, and inexpensivelyserviced. For example, ventilator 2 can be quickly and effectivelydisinfected and/or sterilized. As will be discussed, this may beaccomplished by replacing the entire used inlet airflow assembly 200with a new inlet airflow assembly 200, for example, in the form of areplacement kit, or inlet airflow assembly 200 could be removed and atleast some of the components (e.g., without limitation, cover member202, discussed hereinbelow) thereof could be cleansed using any suitableapproved disinfecting or sterilization procedure, while other components(e.g., without limitation, filtering member 250 and/or filtering member260, discussed hereinbelow) of the assembly 200 could be replaced.

The ability to quickly and easily replace filtering members 250 and 260is highly desirable because such members, which can comprise any knownor suitable gasket, baffle, noise attenuating device and/or filteringmedia, are commonly made from materials such as, for example and withoutlimitation, open cell foam, which can undesirably collect and retaindebris, germs and bacteria. As such, members 250 and 260 must bereplaced or suitably disinfected, in order to properly sterilizeventilator 2. Without the disclosed modular inlet airflow assembly 200,it would be necessary to disassemble a significant portion of ventilator2, or to replace it entirely with a new ventilator, in order to achievethe requisite level of sterilization. Disassembling the ventilator isundesirably time-consuming, and is not a suitable option for the averagepatient and/or caretaker. It also requires an extended amount ofdowntime during which the ventilator is inoperable. The only otheroption, which is to replace the ventilator entirely, is cost-prohibitiveand presents the potential for problematic issues such as, for example,lack of availability of a suitable replacement ventilator or delay inreceiving the replacement, reconfiguring the replacement, etc.

The disclosed inlet airflow assembly 200 overcomes these and otherdisadvantageous by providing a removable modular assembly including acover member 202, which is structured to be selectively coupled toventilator housing 4 at or about an inlet port 30 (FIG. 10) of theventilator. Cover member 202 has first and second opposing sides 204 and206 and an inlet aperture 208 structured to deliver a gas (generallyindicated by reference 38′ in FIGS. 10 and 11) to inlet port 30. Inletairflow assembly 200 disclosed and described herein includes two of theaforementioned filtering members 250 and 260. However, it will beappreciated that any alternative number and/or configuration offiltering members could be employed without departing from the scope ofthe invention.

Inlet airflow assembly 200 preferably includes a fastening mechanism 270such as, for example and without limitation, four screws 272 as shown inthe example of FIG. 10. Fastening mechanism 270 is structured to fastencover member 202 to ventilator housing 4, thereby securing cover member202 and filtering members 250 and 260 with respect thereto. Fasteningmechanism 270 also enables the relatively quick and easy removableand/or replacement of inlet airflow assembly 200 or a portion thereof,for example, by simply loosening and/or removing screws 272. Of course,the present invention contemplates other configurations for fasteningmechanism 270. For example, a snap fit, tongue and groove, friction fit,slotted arrangement or any other suitable fastening technique can beused to couple cover member 202 to ventilator housing 4.

As shown in FIG. 10, exterior surface 10 of ventilator housing 4includes a pocket 29, which extends inwardly from the exterior surfaceto receive inlet airflow assembly 200. When inlet airflow assembly 200and, in particular, cover member 202 therefor, is disposed within pocket29, second side 206 of the cover member is substantially flush withrespect to exterior surface 10 of ventilator housing 4 adjacent thepocket. The flush nature of the inlet airflow assembly, when it isattached to the ventilator housing, can be appreciated with respect toFIGS. 2 and 3, which show the inlet airflow assembly fully mounted onthe ventilator housing.

As with the substantially flush porting block 102, previously discussedhereinabove, the flush design of inlet airflow assembly 200 overcomesthe disadvantages commonly associated with protrusions that extendoutwardly from the ventilator housing 4. In other words, the removableinlet airflow assembly 200 and, for that matter, the other removable orotherwise detachable features (e.g., without limitation, porting block102, detachable battery pack 412, discussed hereinbelow) of ventilator 2do not undesirably interfere with the overall form factor (i.e., overallshape of the exterior surface 10 of the ventilator housing 4) of theventilator.

As best shown in FIG. 11, cover member 202 of inlet airflow assembly 200includes a plurality of walls 210 and 212, which extend substantiallyperpendicularly outwardly from first side 204 of the cover member.Accordingly, when cover member 202 is disposed within pocket 29 (FIGS. 2and 3), walls 210 and 212 of the cover member are structured to extendinto pocket 29 (FIG. 10) in order to direct gas 38′ toward inlet port 30of ventilator 2. Specifically, walls 210 and 212 form an inlet airflowpath 214, which extends from inlet aperture 208 of cover member 202toward inlet port 42 of ventilator 2.

Cover member 202 in the example shown in FIG. 11 is generallyrectangular shaped and includes four peripheral edges 222, 224, 226, 228and four corners 230, 232, 234, and 236. Each of the four screws 272 ofthe example fastening mechanism 270 extends through a corresponding oneof corners 230, 232, 234, and 236, as shown in the exploded view of FIG.10. It will, however, be appreciated that any known or suitablealternative fastening mechanism could be employed in any suitablealternative number and/or configuration, without departing from thescope of the invention.

Walls 210 and 212 of the example cover member 202 include an outer wall210 disposed proximate peripheral edges 222, 224, 226, and 228, and aninner wall 212 spaced inwardly from outer wall 210, as shown. Inner wall212 also extends around at least a portion of inlet port 42 (FIG. 10) ofventilator 2 (FIG. 10). Thus, an inlet airflow path 214 is disposedbetween outer wall 210 and inner wall 212 of cover member 202. Covermember 202 further includes a duct 240 (partially shown) (also shown inFIGS. 2, 3 and 10), which extends inwardly from first side 204 of covermember 202 at or about inlet aperture 208 thereof, in order to directgas 38′ into inlet airflow path 214. The example duct 240 furtherincludes a plurality of louvers 242, to further direct and control theinlet gas 38′, as desired.

At least one of the number of filtering members 250 and 260 of inletairflow assembly 200 is a filter element that is structured to bedisposed between the walls 210 and 212 of cover member 202, in inletairflow path 214. Thus, gas 38′ flows through filter element 260, asshown in phantom line drawing in FIG. 11. As previously discussed,filter element 260 may be made from any known or suitable filteringmedia such as, for example and without limitation, foam (e.g., withoutlimitation, open cell foam). The example filter element 260 includes aplurality of slots 216, 218, and 220 extending therethrough. As shown inphantom line drawing in FIG. 11, when filter element 260 is disposed inthe assembled position, portions of walls 210 and 212 of cover member202 extend through the corresponding slots 216, 218, and 220 of filterelement 260. In this manner, the position of filter element 260 ismaintained with respect to cover member 202. It should be noted,however, that filter element 260 is also preferably selectivelydetachable from over member 202, for example in order to be replaced orsuitably disinfected, as previously discussed.

As noted previously, inlet airflow assembly 200 includes first andsecond filtering members 250 and 260. First filtering member 250 isdisposed adjacent ventilator housing 4, and second filtering member 260is disposed between first filtering member 250 and first side 204 ofcover member 202. First and second filtering members 250 and 260 havefirst and second thicknesses 252 and 262, respectively, wherein secondthickness 262 of second filtering member 260 is greater than firstthickness 252 of first filtering member 250. It will, however, beappreciated that a wide variety of other filtering member embodiments(not shown) are within the scope of the invention. The example firstfiltering member 250 preferably functions, at least in part, as a gasketfor resisting undesired leaking of gas 38′ from between cover member 202and ventilator housing 4. First filtering member 250 also includes ahole 254, which is structured to align within inlet port 42 ofventilator 2 and, in particular, with flow generator 36 (shown insimplified form in FIG. 11), when filter member 250 overlays first side204 of cover member 202.

Accordingly, the disclosed exemplary embodiment of inlet airflowassembly, which in one non-limiting embodiment of the invention, cancomprise a kit containing a new (i.e., replacement) cover member 202 andsuitable filtering members (e.g., without limitation, first and secondfiltering members 250 and 260), enables ventilator 2 to be quickly,easily, and inexpensively sterilized or otherwise serviced, withoutrequiring the substantial disassembly and/or replacement of theventilator.

D. Power Prioritization and Detachable Battery Pack

FIG. 12 shows a schematic representation of ventilator 2 and varioussources of power therefor, in accordance with the principles of theinvention. It will be appreciated that, for simplicity of illustration,internal components of ventilator 2 and the details thereof, have notbeen shown in FIG. 12. The various sources of power, which will now bedescribed, are employable to provide power to any known or suitablecomponent of the ventilator and/or a number of accessories (e.g.,without limitation, a humidifier; an oxygen blender; a pulse oximeter; acarbon dioxide monitor) therefor.

In the example shown and described herein, power is supplied toventilator 2 by way of the following four sources of power:

1) an alternating current (AC) power source 402 (schematically shown insimplified form in FIG. 12) which is electrically connectable to theventilator 2 using a first power connection 404 (e.g., withoutlimitation, a power cord),

2) a lead acid battery 406 such as, for example and without limitation,a 12 VDC car battery or 24 VDC truck battery, which is electricallyconnectable to ventilator 2 using a second power connection 408 (e.g.,without limitation, a battery connector),

3) an internal battery pack 410 (shown in simplified form in hidden linedrawing in FIG. 12) disposed within the interior 6 of the ventilatorhousing 4, and

4) a detachable battery pack 412 (shown in simplified form in phantomline drawing in FIG. 12). As will be discussed, the detachable batterypack 412 is removably coupled to exterior surface 10 of ventilatorhousing 4.

Each of the four power sources 402, 406, 410, and 412 is electricallyconnected to a power control mechanism 26 (shown in simplified form inhidden line drawing in FIG. 12), which is adapted to selectively causepower to be supplied to ventilator 2 from power sources 402, 406, 410,and 412 in accordance with a predetermined hierarchy, described ingreater detail hereinbelow.

Sources of power 402, 406, 410, and 412 and the hierarchy for supplyingpower to ventilator 2 employing the same, greatly improves upon knownventilators which, at best, are structured to operate using one of threesources of power, namely an AC power source, a lead acid battery, or aninternal rechargeable battery pack. Such ventilators (not shown) fail tofurther include detachable battery pack 412 of the invention. As will bediscussed, among other advantages, detachable battery pack 412 improvesthe portability of the ventilator, thereby improving the ability of thepatient to be mobile and to maintain his/her lifestyle while receivingventilation therapy.

It will be appreciated that ventilator 2 could be adapted to beelectrically connectable to any known or suitable AC power source 402such as, for example and without limitation, a 110 VAC power source or a220 VAC power source. The electrical connection between the AC powersource 402 and ventilator 2 may be made by way of any known or suitablepower connection 404. Similarly, it will be appreciated that theexemplary lead acid battery 406 could alternatively comprise any knownor suitable battery of any suitable voltage and/or chemistry, withoutdeparting from the scope of the invention. Lead acid battery 406 canalso be electrically connected to ventilator 2 using any known orsuitable power connection 408.

It will further be appreciated that internal battery pack 410 anddetachable battery pack 412 are preferably rechargeable. In accordancewith one non-limiting embodiment of the invention, each of these batterypacks 410 and 412 comprises a number of lithium ion batteries (see, forexample, lithium ion batteries 424 of detachable battery pack 412, shownin the sectional view of FIG. 14) and, as shown in simplified form, inFIG. 12, the example power control mechanism 26 further includes acharger 28. Accordingly, when ventilator 2 is electrically connected toAC power source 402 or lead acid battery 406, and internal battery pack410 is not fully charged, power source 402 and/or 406 powers charger 28to charge battery pack 410. As will be discussed, charger 28 can also beadapted to charge detachable battery pack 412, if it is not fullycharged.

Detachable battery pack 412 is connectable to ventilator housing 4 inonly one predetermined orientation and, when it is disposed in suchorientation, it does not undesirably protrude from exterior surface 10of ventilator housing 4. This advantageously simplifies the process ofemploying detachable battery pack 412 to power the ventilator by makingit abundantly clear for the patient or caregiver how to properly insertthe detachable battery pack. Furthermore, the fact that detachablebattery pack 412, once inserted in the appropriate orientation does notprotrude from the exterior surface of the ventilator housingadvantageously provides the ventilator housing with a generally uniformform factor (i.e., overall shape of the exterior surface 10 of theventilator housing 4), thereby eliminating the disadvantages commonlyassociated with protrusions. For example and without limitation, bybeing substantially flush with the rest of the housing 4 unintentionalbumping into surrounding objects with a protrusion of housing 4 isavoided, and ventilator 2 is less awkward and/or difficult to holdand/or transport because it has a relatively uniform shape (see FIGS. 1,2 and 3) and associated weight distribution. The flush nature of thedetachable battery pack 412 can be further appreciated with reference toFIGS. 2 and 14, and the unique single-orientation aspect of detachablebattery pack 412 can be further appreciated with respect to thesectional view of FIG. 14.

More specifically, as shown in FIGS. 3, 13, and 14, detachable batterypack 412 includes an enclosure 414 having a first end 416, a second end418 disposed opposite and distal from the first end 416, a first side420, and a second side 422. As shown in FIGS. 2 and 14, only whendetachable battery pack 412 is disposed in the predetermined orientationwithin a cavity 12 defined in ventilator housing 4, is second side 422of enclosure 414 substantially flush with respect to exterior surface 10of the ventilator housing adjacent the cavity, as previously discussed.

A number of batteries 424 (four are shown in the sectional view of FIG.14) such as, for example and without limitation, the aforementionedlithium ion batteries, are enclosed by enclosure 414, and an electricalconnector 426, which is electrically connected to batteries 424, extendsoutwardly from first side 420 of enclosure 414, as shown in FIGS. 13 and14. Electrical connector 426 of detachable battery pack 412 isstructured to be electrically connected to a corresponding electricalconnector 20 disposed within cavity 12 of ventilator housing 4, as shownin FIG. 14.

When detachable battery pack 412 is inserted into cavity 12 ofventilator housing 4 in the correct orientation, electrical connector426 substantially automatically aligns with the corresponding electricalconnector 20 of the ventilator. It will, however, be appreciated thatany known or suitable alternative number and/or configuration ofelectrical connector(s) could be employed, without departing from thescope of the invention. It will also be appreciated that althoughbatteries 424 (FIG. 14) of detachable battery pack 412 and internalrechargeable battery 410 (FIG. 12) are contemplated as being lithium ionbatteries, any known or suitable alternative number, configurationand/or type of batteries could be employed.

Enclosure 414 further includes at least one fastening mechanism, whichin the example shown and described herein includes first and secondprotrusions 428 and 430 extending outwardly from first and second ends416 and 418, respectively, of battery pack enclosure 414. As shown inFIG. 14, protrusions 428 and 430 are structured to engage correspondingrecesses 22 and 24 at opposing ends 14 and 16, respectively, of cavity12 in ventilator housing 4, in order to removably couple enclosure 414to the housing. More specifically, when detachable battery back 412 isinserted into cavity 12 in the appropriate orientation, first protrusion428 engages the corresponding recess 22 at first end 14 of cavity 12.Detachable battery pack 412 is then pivoted (e.g., counterclockwise withrespect to FIG. 14) until second protrusion 430 engages recess 24 atsecond end 16 of cavity 12. In this manner, detachable battery pack 412snaps into the desired predetermined orientation, and is secured withincavity 12 of ventilator housing 4.

In an exemplary embodiment, detachable battery pack 412 further includesa release mechanism 432 (FIGS. 2, 3 and 14) disposed on second side 422of battery pack enclosure 414 so that it is accessible from exterior 8of ventilator housing 4. As best shown in the sectional view of FIG. 14,at least one of the aforementioned first and second protrusions 428 and430 is movably coupled to release mechanism 432 in order that movementof the release mechanism results in a corresponding movement of suchprotrusion(s) 428 and/or 430 to disengage a corresponding recess 22 and24 of cavity 12 of ventilator housing 4, and release detachable batterypack 412 to be removed therefrom.

Continuing to refer to FIG. 14, it will be appreciated that cavity 12 ofhousing 4 of ventilator 2 has a first shape, and that first side 420 ofdetachable battery pack enclosure 414 has a corresponding second shape.Thus, when detachable battery pack 412 is inserted into cavity 12 in thepredetermined orientation, as shown in FIG. 14, the second shape ofbattery enclosure 414 corresponds with the first shape of cavity 12 ofventilator housing 4, in order that detachable battery pack 412 isnested within the cavity. In the example of FIG. 14, which is not meantto limit the scope of the invention in any way, the second end of cavity12 of ventilator housing 4 has an arcuate portion 18, and second end 418of detachable battery pack enclosure 414 has a corresponding arcuateportion 419. The corresponding arcuate portions 18 and 419 facilitateinsertion of battery pack 412 into cavity 12 in the appropriateorientation. In fact, it is substantially impossible for detachablebattery pack 412 to be incorrectly inserted into cavity 12 in any otherorientation. This advantageously eliminates the possibility of thepatient or caretaker incorrectly attaching detachable battery pack 412resulting, for example, in the ventilator not receiving power fromdetachable battery pack 412.

As shown in FIG. 13, the present invention contemplates providingdetachable battery pack 412 with a charge indicator 434 structured toindicate the measured capacity of the number of batteries 424 (FIG. 14)disposed within enclosure 414. As employed herein, the term “measuredcapacity” refers to the remaining power of battery pack 412 as compared,for example, to a fully charged battery pack, which would be at itsmaximum capacity. Charge indicator 434 in the example of FIG. 13includes a plurality of light emitting diodes (LEDs) 435, which areelectrically connected to batteries 424 (FIG. 14) of detachable batterypack 412. LEDs 435 are arranged in a line, with charge indicator 434being designed to illuminate a number of LEDs 435 (i.e., a portion ofthe line), which is indicative of the measured capacity of detachablebattery pack 412.

It will be appreciated that any known or suitable alternative type ofchange indicator other than LEDs 435 could be employed in any suitablenumber and/or configuration, without departing from the scope of theinvention. It will also be appreciated that, although the indication(e.g., illumination of the number of LEDs) could be provided in anyknown or suitable manner (e.g., without limitation, automatically),charge indicator 434 of FIG. 13 includes a resilient tab 436, which isdepressible to complete a circuit (not expressly shown) betweenbatteries 424 (FIG. 14) and LEDs 435, in order to “test” battery pack412 (i.e., illuminate the corresponding number of LEDs 435).

It will further be appreciated that the detachable battery pack 412 mayinclude any known or suitable additional indicia. For example, in thenon-limiting embodiment illustratively shown in FIG. 13, battery pack412 includes indicators 437 and 438 which may comprise, for example andwithout limitation, a charging light (e.g., LED) 437, which could beadapted to blink while detachable battery pack 412 is charging, andanother light (e.g., LED) 438, which could be adapted to illuminate whena predetermined threshold capacity (e.g., a minimum acceptable capacitybefore requiring replacement or transfer to another power source;maximum capacity) of the detachable battery pack is reached.

FIG. 15 shows a method 450 of operating ventilator 2 in accordance withthe predetermined hierarchy of the four aforementioned sources of power402, 406, 410, and 412 (FIG. 12), in accordance with an embodiment ofthe invention. Specifically, at a first step 452, a determination ismade as to whether or not the first power connection (e.g., AC powerconnector 404 of FIG. 12) is electrically connected to the AC powersource 402. If so, power control mechanism 26 (shown in simplified formin FIG. 12) causes power to be supplied to ventilator 2 from the ACpower source 402. As the ventilator is operated using the AC powersource 402, a determination is made, at step 456, whether or not eitherof the internal rechargeable battery pack 410 or the detachable batterypack 412 (FIGS. 2, 3, 10 and 12-14) is fully charged. If not, thencharger 28 charges the appropriate battery pack(s) 410 and/or 412, atstep 458. If both battery packs 410 and 412 are already fully charged,or after they have been fully charged at step 458, the method repeats,starting over again at step 452, with the step of determining whether ornot AC power connector 404 is electrically connected to the AC powersource 402.

If, at step 452, it is determined that AC power connector 404 of theventilator 2 is not electrically connected to AC power source 402, thenthe method moves to step 460 where a determination is made as to whetheror not the second power connection (e.g., lead acid battery connector408 of FIG. 12) is electrically connected to the lead acid battery 406.If so, the method continues to step 462, which is optional.Specifically, at step 462, if necessary, the voltage from the lead acidbattery 406 is converted to the appropriate direct current (DC)requirement of ventilator 2. Then, at step 464, power control mechanism26 causes power to be supplied to the ventilator from the lead acidbattery 406. Meantime, power control mechanism 26 continues to evaluatewhether or not ventilator 2 and, in particular, AC power connector 404,has been connected to AC power source 402. This is true at all timesduring the operation of ventilator 2. In other words, there is apredetermined hierarchy of the four sources of power 402, 406, 410, and412 (all shown in FIG. 12), wherein AC power source 402 preferably takespriority, followed by lead acid battery 406, then detachable batterypack 412, and finally internal rechargeable battery pack 410.

Continuing to refer to method 450 in accordance with the example of FIG.15, if at step 460, it is determined that lead acid battery connector408 of the ventilator 2 is not connected to the lead acid battery 406,then a determination is made, at step 466, as to whether or not thedetachable battery pack 412 is electrically connected to ventilator 2.If the answer to that inquiry is yes, then at step 468, the measuredcapacity of the detachable battery pack 412 is evaluated and, if itexceeds a predetermined threshold (e.g., without limitation, greaterthan 10 percent of the maximum capacity of the detachable battery pack412), then the method moves to step 470. At step 470, power is suppliedto the ventilator using the detachable battery pack 412. If, however, atstep 466, it is determined that the detachable battery pack 412 is notelectrically connected to the ventilator, or at step 468 it isdetermined that the measured capacity of the detachable battery pack 412is less than the predetermined threshold, then the method proceeds tostep 472.

At step 472, the measured capacity of the internal rechargeable batterypack 410 is evaluated and, if it exceeds a predetermined threshold(e.g., without limitation, greater than 10 percent of the maximumcapacity of the internal rechargeable battery pack 410), then the methodmoves to step 474. Alternatively, if the measured capacity of theinternal rechargeable battery pack 410 is not greater than thepredetermined threshold, then the method moves to step 476. At step 474,power is supplied to ventilator 2 to operate the ventilator using theinternal rechargeable battery pack 410, whereas at step 476, power issupplied to the ventilator from both detachable battery pack 412 andinternal rechargeable battery pack 410, on a predetermined shared basis.

More specifically, step 476 generally occurs when both internalrechargeable battery pack 410 and detachable battery pack 412 have ameasured capacity of less than 10 percent of their respective maximumcapacities. Under such circumstances, the supply of power to theventilator will be shared by the two battery packs 410 and 412 accordingto the rule that the battery pack with the greater capacity shallprovide the greater electrical current, such that both battery packs 410and 412 shall reach zero percent capacity substantially simultaneously.In accordance with one non-limiting example, internal rechargeablebattery pack 410 and detachable battery pack 412 together providesufficient power for ventilator 2 to operate under normal operatingconditions, for at least four hours. It will, however, be appreciatedthat battery packs having durations of less than or greater than fourhours, are also within the scope of the invention.

It will, therefore, be appreciated that, in accordance with thedisclosed method 450, the electrical connection or disconnection of anyof the four sources of power 402, 406, 410, and 412 will not result inany interruption of power to the ventilator 2, provided that at leastone of the sources of power 402, 406, 410, and 412 remains electricallyconnected, and is within a predetermined specification (e.g., withoutlimitation, measured capacity). It will also be appreciated thatdetachable battery pack 412 provides a relatively lightweight mechanismfor supplying power to the ventilator 2, substantially indefinitely. Forexample, a plurality of detachable battery packs 412 (only one is shown)could be employed wherein, when one of the detachable battery packs iselectrically connected to the ventilator, the others are being chargedusing any known or suitable charger or battery recharging device (notshown). When detachable battery pack 412, which is electricallyconnected to the ventilator, is discharged to the predeterminedthreshold capacity, it can be quickly and easily replaced with one ofthe charged replacement detachable battery packs. During the exchange ofthe detachable battery packs (i.e., replacing a discharged battery packwith a charged one), the internal battery pack 410 will provide thenecessary power to ventilator, to avoid any unintended interruption inpower.

Accordingly, ventilator 2 of the present invention provides a compactand rugged unit which, with its modular design, is portable tofacilitate patient mobility so as to maintain the lifestyle of thepatient as much as possible. Thus, in accordance with the invention, onesingle portable ventilator 2 is capable of being operated in a varietyof modes to provide a plurality of different ventilation therapies tothe patient. Among other benefits and advantages, the ventilator alsoincludes a user-friendly user interface 300, is capable of recording,transferring, and reporting clinical data, is selectively connectable toa variety of accessories (e.g., without limitation, a humidifier; anoxygen mixer; a pulse oximeter; a carbon dioxide monitor) and devices(e.g., without limitation, the Internet; a printer; a computer). Theventilator also has a number of convenient and cost-effective featuressuch as, for example and without imitation, a porting system 100 forquickly and easily configuring the ventilator for operation in thedesired mode, detachable battery pack 412 and four sources of power, anda modular inlet airflow assembly 200, which can be selectively removedfrom the ventilator 2 to service (e.g., sterilize) the remainder ofventilator, without requiring substantial disassembly or replacement ofthe ventilator.

Although the invention has been described in detail for the purpose ofillustration based on what is currently considered to be the mostpractical and preferred embodiments, it is to be understood that suchdetail is solely for that purpose and that the invention is not limitedto the disclosed embodiments, but, on the contrary, is intended to covermodifications and equivalent arrangements that are within the spirit andscope of the appended claims. For example, it is to be understood thatthe present invention contemplates that, to the extent possible, one ormore features of any embodiment can be combined with one or morefeatures of any other embodiment.

What is claimed is:
 1. A detachable battery pack for a ventilator, theventilator including a housing having an exterior surface and a cavityhaving a first shaped surface interior to the housing and extendinginwardly from the exterior surface, the detachable battery packcomprising: an enclosure structured to be inserted into the cavity, theenclosure including a first end, a second end disposed opposite anddistal from the first end, a first side, and a second side; a number ofbatteries enclosed by the enclosure; an electrical connectorelectrically connected to the number of batteries, the electricalconnector being structured to electrically connect the detachablebattery pack to the ventilator in order to provide power to theventilator; and at least one fastening mechanism structured to removablycouple the enclosure to the housing, wherein the cavity, the enclosure,or both are configured such that the detachable battery pack will onlyfit within the cavity in one predetermined orientation, wherein theenclosure has a second shaped surface that cooperates with the firstshaped surface of the cavity to facilitate insertion of the enclosurewithin the cavity in only the one predetermined orientation, wherein thefirst shaped surface of the cavity and the second shaped surface of theenclosure are configured to allow a pivoting movement relative to eachother about the first end of the enclosure to removably couple theenclosure within the cavity of the housing.
 2. The detachable batterypack of claim 1, wherein the cavity of the housing of the ventilator hasthe first shaped surface, wherein the first side of the enclosure of thedetachable battery pack has the second shaped surface, and wherein, whenthe detachable battery pack is inserted into the cavity in thepredetermined orientation, the second shaped surface of the enclosure isstructured to correspond with the first shaped surface of the housing,in order that the detachable battery pack is nested within the cavity.3. The detachable battery pack of claim 1, wherein the cavity of thehousing of the ventilator includes a first end, a second end disposedopposite and distal from the first end of the cavity, and the firstshaped surface comprises an arcuate shaped surface, wherein the arcuateshaped surface of the cavity is disposed at or about the second end ofthe cavity, wherein the first side of the enclosure includes the secondshaped surface comprising an arcuate shaped surface disposed at or aboutthe second end of the enclosure, and wherein the arcuate shaped surfaceof the enclosure corresponds to the arcuate shaped surface of the cavityin order to facilitate insertion and pivoting of the battery pack intothe cavity in the predetermined orientation.
 4. The detachable batterypack of claim 3, wherein the arcuate shaped surface of the cavity isprovided on a surface interior to the housing at the second end of thecavity and the arcuate shaped surface of the enclosure is provided on anexternal surface of the enclosure at the second end.
 5. The detachablebattery pack of claim 3, wherein the arcuate shaped surface issubstantially concealed by the cavity upon insertion.
 6. The detachablebattery pack of claim 1, wherein the cavity of the housing of theventilator has a first end and a second end disposed opposite and distalfrom the first end of the cavity, wherein the at least one fasteningmechanism comprises a first protrusion extending outwardly from theenclosure of the detachable battery pack at or about the first end ofthe enclosure, and a second protrusion extending outwardly from theenclosure of the detachable battery pack at or about the second end ofthe enclosure, and wherein, when the detachable battery pack is insertedinto the cavity in the appropriate orientation, the first protrusion isstructured to engage the housing at or about the first end of thecavity, and the second protrusion is structured to engage the housing ator about the second end of the cavity, in order that the detachablebattery pack snaps into the predetermined orientation and is securedwithin the cavity.
 7. The detachable battery pack of claim 6, whereinthe at least one fastening mechanism further comprises a releasemechanism disposed on the second side of the enclosure of the detachablebattery pack, and wherein at least one of the first protrusion and thesecond protrusion is movably coupled to the release mechanism, in orderthat movement of the release mechanism results in a correspondingmovement of the at least one of the first protrusion and the secondprotrusion, thereby disengaging the detachable battery pack from thehousing of the ventilator.
 8. The detachable battery pack of claim 1,wherein, when the enclosure is disposed in the predetermined orientationwithin the cavity, the second side of the enclosure is structured to besubstantially flush with respect to the exterior surface of the housingadjacent the cavity.
 9. The detachable battery pack of claim 1, whereinthe enclosure further include a charge indicator structured to indicatethe measured capacity of the number of batteries.
 10. The detachablebattery pack of claim 9, wherein the charge indicator comprises aplurality of LEDs electrically connected to the number of batteries, andwherein the number of batteries illuminate a number of the LEDscorresponding to the measured capacity of the number of batteries of thedetachable battery pack.
 11. The detachable battery pack of claim 1,wherein the ventilator further includes an electrical connector disposedwithin the cavity of the housing, wherein the electrical connector ofthe detachable battery pack is disposed on the first side of theenclosure of the detachable battery pack, and wherein, when thedetachable battery pack is inserted into the cavity in the predeterminedorientation, the electrical connector of the detachable battery pack isstructured to align with and electrically connect to the electricalconnector of the ventilator.
 12. The detachable battery pack of claim 1,wherein surfaces of the first end, the second end, the first side, aleft side, and a right side of the enclosure are substantially concealedby the cavity, and a surface of the second side is exposed.
 13. Aventilator comprising: (a) a housing having an exterior surface and acavity having a first shaped surface interior to the housing andextending inwardly from the exterior surface; and (b) a detachablebattery pack comprising: (1) an enclosure structured to be inserted intothe cavity, the enclosure including a first end, a second end disposedopposite and distal from the first end, a first side, and a second side;(2) a number of batteries enclosed by the enclosure; (3) an electricalconnector electrically connected to the number of batteries, theelectrical connector being structured to electrically connect thedetachable battery pack to the ventilator in order to provide power tothe ventilator; and (4) at least one fastening mechanism structured toremovably couple the enclosure to the housing, wherein the cavity, theenclosure, or both are configured such that the detachable battery packwill only fit within the cavity in one predetermined orientation,wherein the enclosure has a second shaped surface that cooperates withthe first shaped surface of the cavity to facilitate insertion of theenclosure within the cavity in only the one predetermined orientation,wherein the first shaped surface of the cavity and the second shapedsurface of the enclosure are configured to allow a pivoting movementrelative to each other about the first end of the enclosure to removablycouple the enclosure within the cavity of the housing.
 14. Theventilator of claim 13, wherein the cavity of the housing of theventilator includes a first end, a second end disposed opposite anddistal from the first end of the cavity, and the first shaped surfacebeing an arcuate shaped surface, wherein the arcuate shaped surface ofthe cavity is disposed at or about the second end of the cavity, whereinthe first side of the enclosure includes the second shaped surface, thesecond shaped surface being an arcuate shaped surface disposed at orabout the second end of the enclosure, and wherein the arcuate shapedsurface of the enclosure corresponds to the arcuate shaped surface ofthe cavity in order to facilitate insertion and pivoting of the batterypack into the cavity in the predetermined orientation.
 15. Theventilator of claim 13, wherein the cavity of the housing of theventilator has a first end and a second end disposed opposite and distalfrom the first end of the cavity, wherein the at least one fasteningmechanism of the detachable battery pack comprises a first protrusionextending outwardly from the enclosure of the detachable battery pack ator about the first end of the enclosure, and a second protrusionextending outwardly from the enclosure of the detachable battery pack ator about the second end of the enclosure, and wherein, when thedetachable battery pack is inserted into the cavity of the housing ofthe ventilator in the appropriate orientation, the first protrusionengages the housing of the ventilator at or about the first end of thecavity, and the second protrusion engages the housing of the ventilatorat or about the second end of the cavity, in order that the detachablebattery pack snaps into the predetermined orientation and is securedwithin the cavity.
 16. The ventilator of claim 15, wherein the at leastone fastening mechanism of the detachable battery pack further comprisesa release mechanism disposed on the second side of the enclosure of thedetachable battery pack, and wherein at least one of the firstprotrusion and the second protrusion is movably coupled to the releasemechanism, in order that movement of the release mechanism results in acorresponding movement of the at least one of the first protrusion andthe second protrusion, thereby disengaging the detachable battery packfrom the housing of the ventilator.
 17. The ventilator of claim 13,wherein, when the enclosure of the detachable battery pack is disposedin the predetermined orientation within the cavity of the housing of theventilator, the second side of the enclosure is substantially flush withrespect to the exterior surface of the housing adjacent the cavity. 18.The ventilator of claim 13, wherein the housing of the ventilatorfurther includes an electrical connector disposed within the cavity,wherein the electrical connector of the detachable battery pack isdisposed on the first side of the enclosure of the detachable batterypack, and wherein, when the detachable battery pack is inserted into thecavity of the housing of the ventilator in the predeterminedorientation, the electrical connector of the detachable battery packaligns with and electrically connects to the electrical connector of theventilator.
 19. The ventilator of claim 13, wherein surfaces of thefirst end, the second end, the first side, a left side, and a right sideof the enclosure are substantially concealed by the cavity, and asurface of the second side is exposed.